ICDcodes.org
FY2027

I01.2 vs I40

I01.2 and I40 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.

The official note, declared on I40
acute rheumatic myocarditis (I01.2)
I01.2

Acute rheumatic myocarditis

Billable
Chapter 9
Diseases of the circulatory system
Section
I00-I02
Use when the record says
  • Any condition in I00 with myocarditis
Indexed under
  • Myocarditis › active › rheumatic (with arteriosclerosis)(chronic)(fibroid) (interstitial) (old) (progressive) (senile)
  • Myocarditis › acute or subacute › rheumatic (with arteriosclerosis)(chronic)(fibroid) (interstitial) (old) (progressive) (senile)
  • Myocarditis › rheumatic › active or acute (with arteriosclerosis)(chronic)(fibroid) (interstitial) (old) (progressive) (senile)
  • Rheumatic › myocarditis › active or acute (acute) (subacute)
  • Degeneration, degenerative › myocardial, myocardium › with rheumatic fever › active, acute or subacute
I40

Acute myocarditis

Not billable
Chapter 9
Diseases of the circulatory system
Section
I30-I5A
Use when the record says
  • subacute myocarditis

Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027